php模拟顺序栈基本操作

一、总结

写函数什么永远记住边界情况：比如 echo "栈已满！<br/>" ; 栈已空这种，那就能多考虑几种情况，代码就很正宗了

1、对象生成和java一样，都是new关键字

2、 属性方法都是 -> 访问

3、对象的操作只是比java中少了变量类型而已，php不需要变量类型

二、代码

 1 /**
 2  * Class Stack
 3  * 用PHP模拟顺序栈的基本操作
 4  */
 5 class Stack{
 6     //用默认值直接初始化栈了，也可用构造方法初始化栈
 7     private $top = -1;
 8     private $maxSize = 5;
 9     private $stack = array();
10 
11     //入栈
12     public function push($elem){
13         if($this->top >= $this->maxSize-1){
14             echo "栈已满！<br/>";
15             return;
16         }
17         $this->top++;
18         $this->stack[$this->top] = $elem;
19     }
20     //出栈
21     public function pop(){
22         if($this->top == -1){
23             echo "栈是空的！";
24             return ;
25         }
26         $elem = $this->stack[$this->top];
27         unset($this->stack[$this->top]);
28         $this->top--;
29         return $elem;
30     }
31     //打印栈
32     public function show(){
33         for($i=$this->top;$i>=0;$i--){
34             echo $this->stack[$i]." ";
35         }
36         echo "<br/>";
37     }
38 }
39 
40 $stack = new Stack();
41 $stack->push(3);
42 $stack->push(5);
43 $stack->push(8);
44 $stack->push(7);
45 $stack->push(9);
46 $stack->push(2);
47 $stack->show();
48 $stack->pop();
49 $stack->pop();
50 $stack->pop();
51 $stack->show();